The present invention relates to a semiconductor integrated circuit provided with a fuse.
The density of the semiconductor integrated circuit is continuously being increased and therefore the size of the chip employed is also continuously being enlarged. This makes it difficult to enable all of circuits on a chip to be operated without failure. A semiconductor integrated circuit provided with a fuse has been developed to overcome this problem. Degraded circuit or bit portions are removed by burning out the fuse with the current, and redundant circuits or bits are added to compensate for the degraded circuit or bit portions which are removed.
There has also been developed a PROM (programmable read only memory) in which data is written by burning out the fuse.
A fuse consisting of polycrystalline silicon is employed in conventional semiconductor integrated circuits. Polycrystalline silicon is very sensitive to change and the grain size varies readily upon a slight change in its manufacturing conditions. The variation of the grain size causes the current value for burning out the fuse to become irregular and therefore program error frequently occurs. These conventional semiconductor integrated circuits therefore have low reliability.